Digital setup accuracy for moderate crowding correction with fixed orthodontic appliances: a prospective study.

OBJECTIVES: To evaluate the accuracy of a semi-automatic 3D digital setup process in predicting the orthodontic treatment outcome achieved by labial fixed appliances. SUBJECTS AND METHODS: Twenty-five adult patients (18 to 24 years old) with class I malocclusion and moderate crowding were prospectively enrolled and received treatment on both jaws through the straight-wire technique. Prior to treatment commencement, a semi-automatic digital setup simulating the predicted treatment outcome was performed for each patient through Orthoanalyzer software (3Shape®, Copenhagen, Denmark) to obtain the prediction model. This was compared to the final outcome model through 3D superimposition methods. Metric variables and inspection of color-coded distance maps were used to detect how accurately the digital setup predicts the actual treatment outcome. RESULTS: The mean absolute distances (MAD) between the superimposed dental arches of the predicted and the final models were: 0.77 ± 0.13 mm following superimposition on the palate, 0.52 ± 0.06 mm following superimposition on the maxillary dental arch, and 0.55 ± 0.15 mm following superimposition on the mandibular dental arch. The MAD at the palatal reference area was 0.09 ± 0.04 mm. Visualization of color-coded distance maps indicated that the digital setup accurately predicted the final teeth position in a few cases. Almost half of the cases had posteriorly wider upper and lower dental arches and palatally/lingually positioned or inclined anterior teeth, whereas the rest still showed errors within 2-3 mm, distributed over the entire dental arches with no distinct pattern. CONCLUSIONS: The accuracy of semi-automatic prediction of the labial fixed appliance treatment outcome in Class I cases with moderate crowding is not yet sufficient. While average measures showed deviations less than 1 mm, examination of individual color-coded distance maps revealed significant disparities between the simulated and the actual results.

Duration of orthodontic treatment with clear aligners versus fixed appliances in crowding cases: a systematic review.

OBJECTIVE: To critically appraise and assess the currently observed evidence about the difference in orthodontic treatment duration between clear aligners and fixed appliances in crowding cases. MATERIALS AND METHODS: An electronic search without limitations was conducted from inception to June 2023 covering nine databases: The Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Scopus, Web of Science, Google Scholar, Trip, CINAHL via EBSCO, EMBASE via OVID and ProQuest. Randomized controlled trials (RCTs) and matched non-randomized studies were included in this systematic review. Risk of Bias was assessed via Cochrane's tool (RoB 2) for RCTs and ROBINS-I tool for non-randomized studies. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework was employed to evaluate the overall quality of evidence. RESULTS: Out of the 3537 articles initially identified, ten eligible studies were included in this systematic review; six were RCTs. Only one study offered extraction-based treatment, while the other nine adopted non-extraction treatments. According to the GRADE, there is low evidence that treatment duration in mild to moderate crowding cases with clear aligners is similar to that in fixed orthodontic appliances. Meta-analysis was not administered due to high inconsistency. CONCLUSIONS: Based on currently available information, there was no significant difference in the treatment duration between the CA and FA groups in mild to moderate crowding cases. Further well-performed RCTs, especially in severe cases, are required. CLINICAL RELEVANCE: Time efficiency is an essential outcome measure for clinical orthodontic practice. While the type of appliance used is a critical determinant of treatment duration, orthodontists should be aware of other factors that can significantly impact treatment time, such as patient and treatment-related factors.

Impact of treament with orthodontic aligners on the oral health-related quality of life.

BACKGROUND: There is an increasing interest in information on the effects of orthodontic aligners on the oral health-related quality of life (OHRQoL) of people. AIM: To compare the impact of orthodontic aligners versus conventional fixed appliances on OHRQoL, using a validated tool and controlling for sociodemographic and clinical variables. METHOD: Sixty-one individuals participated in this study. Group 1 (G1) consisted of 33 individuals under treatment with orthodontic aligners and Group 2 (G2) comprised 28 individuals under treatment with conventional fixed appliances. OHRQoL was evaluated with the Oral Health Impact Profile (OHIP-14) in which 14 items are distributed across seven dimensions: functional limitation, physical pain, psychological discomfort, physical disability, psychological disability, social disability, and handicap. The higher the score, the more negative is the perception of the individual regarding his/her OHRQoL. Descriptive statistics, Mann-Whitney test, and Poisson regression were performed. Effect Size (ES) and Minimal Clinically Important Difference (MCID) were also determined. RESULTS: Participants' mean age was 30.69 years. Individuals in G1 had a significantly lower score for physical pain and the total score of OHIP-14 compared to individuals in G2 (p < 0.05). The ES was large (ES = 0.74) for physical pain and moderate (ES = 0.46) for the total score. The ES was moderate for physical disability (ES = 0.50). The difference between groups for physical pain (1.30) and for physical disability (0.90) was greater than the MCID (0.87 and 0.88, respectively). Poisson regression showed that G2 individuals showed a score for physical pain 1.39 times higher than those of G1 in the adjusted model (OR = 1.39, [1.03-1.89], p = 0.031). CONCLUSION: Those under treatment with orthodontic aligners have a more positive perception of OHRQoL compared to those wearing fixed appliances.

Comparison of efficacy of thermoplastic retainer with round and rectangular bonded lingual wire retainer in the mandible two years after orthodontic treatment: a randomised controlled trial.

OBJECTIVE: To analyse three protocols in maintaining the stability of orthodontic therapy results and their effect on gingival health. MATERIALS AND METHODS: Sixty-six subjects (pre-therapeutic age 11-18 years; 68% female) randomly allocated into three retention groups of equal size were analysed. The first group had a 0.673 × 0.268 mm (0.027 × 0.011 inches) rectangular braided steel retention wire bonded to the lingual surfaces of all mandibular teeth from canine to canine, and the second group had a 0.406 mm (0.016 inches) round twisted steel wire. The third group was the control, without wires, and only with vacuum-formed retainers. All three groups had vacuum-formed removable retainers in the maxilla. The frequency of wire detachment/breakage/loss of retainer, the occurrence of crowding of mandibular incisors, and changes in intercanine width and gingival health were monitored. RESULTS: Incidence and severity of relapse differed between groups (p = 0.001 and 0.049) being most common in the removable retainer group (incidence 68.2%; severity 0.7 ± 1.0 mm), followed by the round wire group (36.4%; 0.5 ± 1.2 mm) and rectangular wire group (13.6%; 0.1 ± 0.1 mm). The intercanine width decreased more without a bonded retainer (incidence 68.2%; severity 0.5 ± 0.7 mm) and with the round wire more (45.5%; 0.5 ± 0.7 mm) than with the rectangular (27.3%; 0.1 ± 0.3 mm). The difference was significant for incidence (p = 0.025), but not severity. Detaching of the wires/breakage/loss of retainer was similar. There were no significant differences in the accumulation of biofilm, calculus and gingivitis between appliances. CONCLUSION: A rectangular wire is the most effective in retention, and the impact of retention appliances on gingival health is similar. TRIAL REGISTRATION: ClinicalTrials.gov, NCT05121220. Registered 02 October 2021 - Retrospectively registered. CLINICAL RELEVANCE: Studying guidelines for reducing relapse, proper use of materials and appliances, the behavior of retention wires according to their profile in the retention phase, and possibilities of maintaining oral health will contribute to improving the stability of orthodontic therapy results.

Stability, survival, patient satisfaction, and cost-minimization of CAD/CAM versus conventional multistranded fixed retainers in orthodontic patients: a 2-year follow-up of a two-centre randomized controlled trial.

BACKGROUND: CAD/CAM (computer-aided design/computer-aided manufacturing) fixed retainers (FRs) as an alternative to multistranded FRs to maintain orthodontic treatment outcome. OBJECTIVES: The primary aim was to compare CAD/CAM versus conventional multistranded FRs in terms of stability until 2 years. Secondary outcomes were failure rates, patient satisfaction, and cost-minimization. TRIAL DESIGN: 2-arm parallel, two-centre randomized controlled trial. METHODS: Patients were randomized to CAD/CAM or conventional FRs in both arches, in a 1:1 ratio and blocks of four. Allocation concealment was secured by using sequentially numbered envelopes. Patients were blinded. FRs were bonded at the end of treatment, and patients were recalled after 12 and 24 months. First-time retainer failures were recorded and digital impressions were taken. Arch widths and lengths, as well as Little's Irregularity Index (LII), were measured. Additionally, patients answered satisfaction questionnaires. Linear mixed models were applied for measurements and patient satisfaction. Survival analyses were estimated with Kaplan-Meier curves, along with Cox-regression modelling. Cost-minimization analysis was undertaken. RESULTS: One hundred and eighty-one patients were randomized (98 in Centre 1, and 83 in Centre 2): 90 in CAD/CAM and 91 in conventional group. One hundred and fifty three patients attended T24 follow-up. There were no significant differences in LII and arch dimensions between groups for failure-free patients. Within 24 months, 34% maxillary CAD/CAM FRs and 38% maxillary conventional FRs failed, along with 42% mandibular CAD/CAM FRs and 40% mandibular conventional FRs, with no significant difference in survival between groups (hazard ratios conventional to CAD/CAM: maxillary arch: 1.20 [P = 0.46], mandibular arch: 0.98 [P = 0.94]). There were no significant differences in patient satisfaction between groups. No harms were observed. Cost-minimization analysis showed that CAD/CAM FRs were slightly cheaper than conventional FRs. CONCLUSIONS: There were no clinically significant differences in LII, arch widths, and lengths between CAD/CAM and conventional FRs after 24 months. There were no differences in failures and patient satisfaction between groups. CAD/CAM FRs were slightly cheaper than conventional FRs. TRIAL REGISTRATION: ClinicalTrials.gov NCT04389879.

Elemental composition, corrosion resistance and mechanical properties of computer-aided design and computer-aided manufacturing fixed retainers versus conventional fixed retainers.

PURPOSE: To investigate the elemental composition, corrosion resistance, and mechanical properties of computer-aided design and computer-aided manufacturing (CAD-CAM) retainers versus conventional fixed retainers (FRs). METHODS: Eight different retainer wires were investigated. Energy dispersive X-ray spectroscopy was used to determine the elemental composition. Leakage was analysed according to ISO 10271:2020 guidelines. Hardness was tested using the Vickers method with a load of 0.3 kg. The tensile force and tensile strength were evaluated. Multiple comparisons among wires of hardness, tensile force, and strength were conducted using the Welch t-test, with Bonferroni correction. RESULTS: Nickel was present in all wires. The CAD-CAM-FR wire, which contained more nickel than the other wires, had no measurable leakage. The gold-plated wires had the highest total leakage, but did not exceed the ISO standard limit. The hardness of the stainless-steel twisted wires was the highest and that of the CAD-CAM-FR wire was the lowest. The tensile strength of the CAD-CAM-FR wire was significantly lower than that of the other wires and similar to the other twisted-wire retainers. CONCLUSION: The CAD-CAM-FR wire is likely to have high corrosion resistance and flexibility due to its low hardness.

Civil liability of orthodontists and aligner manufacturers in the treatment with orthodontic aligners.

INTRODUCTION: The use of clear aligners as an alternative to fixed orthodontic appliances has become popular due to the aesthetic demands of adult patients seeking orthodontic treatment. However, orthodontists' lack of knowledge about the legal consequences of their activities, and the lack of solid scientific evidence raise concerns regarding civil liability in this type of treatment. Marketing campaigns of manufacturing companies often exaggerate promises of results, and ignore the lack of scientific evidence. Patients, as consumers, are protected by the Consumer Protection Code, whereas orthodontists are considered treatment providers. Therefore, they can be held liable for damage caused to patients, whether by subjective or objective fault. OBJECTIVE: This article aims to identify the civil responsibilities of orthodontists and aligner manufacturing companies, by means of a literature review, providing basic legal guidance to help professionals protect themselves from possible lawsuits related to treatment with orthodontic aligners. CONCLUSIONS: The study highlights the importance of knowledge of legal notions in treatments with orthodontic aligners by orthodontists, who should legally safeguard themselves through individual written contracts, avoiding obligation of results. In addition, in cases of legal claims, it is possible that the manufacturing companies are jointly and severally liable for possible damages claimed by the patient.

Content analysis of AI-generated (ChatGPT) responses concerning orthodontic clear aligners.

OBJECTIVES: To assess the accuracy of ChatGPT answers concerning orthodontic clear aligners. MATERIALS AND METHODS: A cross-sectional content analysis of ChatGPT generated responses to queries related to clear aligner treatment (CAT) was undertaken. A total of 111 questions were generated by three orthodontists based on a set of predefined domains and subdomains. The artificial intelligence (AI)-generated (ChatGPT) answers were extracted and their accuracy was determined independently by five orthodontists. The accuracy of answers was assessed using a prepiloted four-point scale scoring rubric. Descriptive statistics were performed. RESULTS: The total mean accuracy score for the entire set was 2.6 ± 1.1. It was noted that 58% of the AI-generated answers were scored as objectively true, 18% were selected facts, 9% were minimal facts, and 15% were false. False claims included the ability of CAT to reduce the need for orthognathic surgery (4.0 ± 0.0), improve airway function (3.8 ± 0.5), achieve root parallelism (3.6 ± 0.5), alleviate sleep apnea (3.8 ± 0.5), and produce more stable results compared to fixed appliances (3.8 ± 0.5). CONCLUSIONS: The overall level of accuracy of ChatGPT responses to questions concerning CAT was suboptimal and lacked citations to relevant literature. Ability of the software to offer current and precise information was limited. Therefore, clinicians and patients must be mindful of false claims and relevant facts omitted in the answers generated by ChatGPT.

Clear aligners vs fixed appliances: which treatment option presents a higher incidence of white spot lesions, plaque accumulation and salivary caries-associated bacteria?

DATA SOURCES: Multiple databases were searched electronically in order to find relevant studies for the meta-analysis. These included: MEDLINE, Scopus, Embase, Google Scholar, Clinical trial registry, OpenGrey and ProQuest. Two independent reviewers were used to assess the certainty of evidence and risk of bias. STUDY SELECTION: The eligibility criteria for the studies were as follows: randomized controlled trials and non-randomized studies that compared the incidence and severity of white spot lesions, plaque accumulation and salivary caries-associated bacteria between clear aligners and conventional fixed appliances in patients undergoing orthodontic treatment. In total, 14 studies met the criteria, with 8 of the studies deemed suitable for meta-analysis. DATA EXTRACTION AND SYNTHESIS: Two independent reviewers carried out data extraction with a form composed of the following subheadings: Study information, Population, Intervention and control, Outcomes. The risk of bias was assessed using the ROBINS-I tool and a revised version of ROB-2, the Cochrane risk of bias tool. GRADEpro GDT software was used to assess the quality of evidence. To calculate the size of the effect of the different treatment options, the mean and standard deviation were extracted from all included studies. Heterogeneity was assessed using chi square and I2 tests, with a p value below 10% being indicative of significant heterogeneity for the chi square and a value greater than 50% being indicative of significant heterogeneity for the I2 tests. RESULTS: With regards to plaque accumulation, the effect size was measured at 3 time points: 3 months, 6 months and 12 months. At all the time points assessed within the 8 studies included in the meta-analysis, the effect size was greater for clear aligners. With regards to white spot lesions, 4 studies were available to assess the incidence of white spot lesions. Three studies reported a lower risk of developing white spot lesions in clear aligners, where one study reported no difference. As all 4 studies used different methodologies, a meta-analysis was not possible. With regards to salivary caries-associated bacteria, 2 studies reported a higher concentration of bacteria in conventional fixed appliances. Meta-analysis was not performed due to lack of studies. CONCLUSIONS: Based on the evidence presented, clear aligners appear to be associated with less plaque accumulation and less salivary caries-associated bacteria when compared with conventional fixed appliances. Therefore, this could be related to the reduced incidence of white spot lesions in clear aligners.

Influence of casein phosphopeptide-amorphous calcium phosphate on the surface topography and composition of nickel-titanium archwires during orthodontic treatment with fixed appliances.

PURPOSE: To investigate the surface topography and nickel content of nickel-titanium (NiTi) archwires exposed to either routine oral hygiene or a prophylactic regimen with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) during orthodontic treatment. METHODS: This in vivo study involved 40 orthodontic patients with fixed appliances, who were randomly assigned to either a routine oral hygiene group or a CPP-ACP supplementary regimen group. Twenty new NiTi archwires served as controls. All archwires underwent scanning electron microscopy and energy-dispersive spectroscopy to evaluate their surface topography and elemental composition. The nickel content was quantified as a percentage of total weight and the Ni/Ti ratio, and statistical comparisons were made using pairwise tests. RESULTS: Wires exposed to fluoride toothpaste showed signs of pitting corrosion, deep grooves, and corrosion debris. In contrast, wires exposed to supplementary CPP-ACP exhibited smooth surface areas interspersed with microdefects and deposits. Statistically significant differences in nickel content were found between the new and retrieved archwires, as well as between wires exposed to routine oral hygiene and CPP-ACP (P < 0.001). The archwires exposed to CPP-ACP had the lowest nickel content (P < 0.001). CONCLUSION: The use of CPP-ACP holds promise for application as a safe anticariogenic agent with possible protective properties during orthodontic treatment.

Stability of class II correction with the Austro Repositioner associated with multi-brackets fixed appliances in dolichofacial patients.

BACKGROUND: The purposes of the present study were to evaluate the changes produced by the Austro Repositioner, and to assess the stability of Class II malocclusion treatment with the Austro Repositioner associated with fixed appliances and its capacity to control the vertical dimension in dolichofacial patients. METHODS: A group of patients with Class II malocclusion due to mandibular retrognathism and a dolichofacial growth pattern treated with the Austro Repositioner combined with fixed appliances were compared to a matched untreated control group of subjects with Class II malocclusion. Evaluations were made on the basis of lateral cephalograms taken at T1 (initial records), T2 (end of treatment), and T3 (1 year after treatment). Statistical comparisons were performed with paired- and two-sample t tests. RESULTS: The experimental (treated) group comprised 30 patients, 14 boys and 16 girls, and the control group comprised 30 subjects (15 boys and 15 girls) with similar ages at T1, T2 and T3. In the treated group, a significant decrease in the ANB angle was found (- 3.79 ± 1.46; p < 0.001). No significant differences were found in the maxillary skeletal measurements. In contrast, the SNB angle showed a significant increase of 3.77 ± 1.49 in the treated group compared with a nonsignificant increase of 0.77 ± 1.55 in the control group (p = 0.002). Vertical changes showed a significant decrease in the FMA angle (- 3.36 ± 1.62), while the lower anterior facial height distance and the overbite increased significantly in the treated group, reflecting a change in vertical dimensions after treatment. No significant changes were observed in either the treated or control group during the one-year posttreatment period; thus, the treatment results remained stable. CONCLUSIONS: The Austro Repositioner combined with fixed appliances could be considered an optimal treatment modality in Class II dolichofacial patients.

Relapse and failure rates between CAD/CAM and conventional fixed retainers: a 2-year follow-up of a randomized controlled clinical trial.

BACKGROUND: Retention has been always considered a major challenge in orthodontics. Recently computer-aided design/computer-aided manufacturing (CAD/CAM) fixed retainers (FRs) have been introduced as a marked development in retainer technology, offering potential advantages. OBJECTIVE: The objective of this study was to compare the differences in relapse and failure rates in patients treated with FRs using CAD/CAM technology, lab-based technique, and chairside method. TRIAL DESIGN: A double-blinded, prospective, randomized controlled clinical trial was conducted over a 2-year period at a single centre. INTERVENTIONS: These patients were divided into three groups: CAD/CAM group with multistranded Stainless Steel wires (CAD/CAM, n = 14), lab group with the same multistranded wires (lab, n = 15), and a chairside group with Stainless Steel Ortho-FlexTech wires (chairside, n = 14). OUTCOMES: Inter-canine width (ICW) and Little's irregularity index were digitally measured from scans at the orthodontic debonding (T1), 6-month retention (T2), 1-year retention (T3), and 2-year retention (T4) visits. All forms of failure were documented and analyzed. RANDOMIZATION: Participants were randomly assigned to the three groups using online randomization software (randomization.com) by a statistician who was not involved in the study. BLINDING: Patients were blinded in terms of the FR group to which they were each randomly assigned. The principal investigator was blinded upon data analysis since patients' records were coded to minimize observer and measurement bias. RESULTS: Initially 81 patients were assessed for eligibility. Seventy-five patients were randomly allocated into the three study groups. After 2-year follow-up, 43 patients came back for the follow-up and were analyzed. The CAD/CAM group showed significantly less reduction in ICW compared to the chairside group at all time intervals (P < .05) and compared to the lab group at 6 months (P = .038). In terms of LII, the CAD/CAM group exhibited significantly less change than the chairside and lab groups at all time intervals (P < .05). The CAD/CAM group had the lowest failure rate (21.4%), followed by chairside group (28.6%) and then lab group (33.3%), however the differences were insignificant. No harms were observed in the current study. CONCLUSION: Within 2 years of fixed retention, CAD/CAM FRs showed significantly less relapse than lab-based and chairside FRs. However, there was no significant difference in failure rates among the groups. TRIAL REGISTRATION: NCT05915273.

Periodontal indexes of two types of 3 x 3 retainers: 0.032-in SS V-loop versus 0.0215-in SS coaxial - a randomized crossover trial.

OBJECTIVE: This randomized crossover trial evaluated periodontal indexes of two types of 3 x 3 retainers (a modified 0.032-in SS V-loop retainer and a conventional 0.0215-in SS coaxial wire retainer) after bonded for six months. Also, bonded failure rate, and a questionnaire about comfort, ease of cleaning and overall preference were recorded. MATERIAL AND METHODS: 15 patients were enrolled in this study who used both retainers for six months each, having a 15-day wash-out interval between each bonded retainer usage. The following periodontal index were recorded: Plaque Index (PI), Calculus Index (CI) and Gingival Index (GI). Patients answered a questionnaire to assess comfort, ease of cleaning and overall retainer-type preference. Rate of bonding failure was also evaluated. RESULTS: V-Loop retainer showed higher PI (P<0.05) as compared to conventional 0.0215-in coaxial wire retainer. However, CI and GI presented no statistically significant differences between both types of retainers. The conventional 0.0215-in coaxial wire retainer was chosen as the most comfortable (p<0.05), although no statistically significant differences were found for all other questionnaire answers. Bonding failure events were more observed in the 3x3 V-Loop retainer (p<0.002), as compared to the conventional 0.0215-in coaxial retainer. CONCLUSION: V-Loop retainer showed higher PI (p<0.05), higher bonding failure rate and less comfortable, as compared to conventional 0.0215-in coaxial wire.

Comparative assessment of orthodontic clear aligner versus fixed appliance for anterior retraction: a finite element study.

BACKGROUND: The aim of this study is to conduct a comparative evaluation of different designs of clear aligners and examine the disparities between clear aligners and fixed appliances. METHODS: 3D digital models were created, consisting of a maxillary dentition without first premolars, maxilla, periodontal ligaments, attachments, micro-implant, 3D printed lingual retractor, brackets, archwire and clear aligner. The study involved the creation of five design models for clear aligner maxillary anterior internal retraction and one design model for fixed appliance maxillary anterior internal retraction, which were subsequently subjected to finite element analysis. These design models included: (1) Model C0 Control, (2) Model C1 Posterior Micro-implant, (3) Model C2 Anterior Micro-implant, (4) Model C3 Palatal Plate, (5) Model C4 Lingual Retractor, and (6) Model F0 Fixed Appliance. RESULTS: In the clear aligner models, a consistent pattern of tooth movement was observed. Notably, among all tested models, the modified clear aligner Model C3 exhibited the smallest differences in sagittal displacement of the crown-root of the central incisor, vertical displacement of the central incisor, sagittal displacement of the second premolar and second molar, as well as vertical displacement of posterior teeth. However, distinct variations in tooth movement trends were observed between the clear aligner models and the fixed appliance model. Furthermore, compared to the fixed appliance model, significant increases in tooth displacement were achieved with the use of clear aligner models. CONCLUSIONS: In the clear aligner models, the movement trend of the teeth remained consistent, but there were variations in the amount of tooth displacement. Overall, the Model C3 exhibited better torque control and provided greater protection for posterior anchorage teeth compared to the other four clear aligner models. On the other hand, the fixed appliance model provides superior anterior torque control and better protection of the posterior anchorage teeth compared to clear aligner models. The clear aligner approach and the fixed appliance approach still exhibit a disparity; nevertheless, this study offers a developmental direction and establishes a theoretical foundation for future non-invasive, aesthetically pleasing, comfortable, and efficient modalities of clear aligner treatment.

A retrospective study of alveolar bone remodelling after anterior retraction in orthodontic tooth extraction cases with clear aligners and fixed appliances.

OBJECTIVES: To evaluate alveolar bone dimensions and its relationship with tooth movement (retraction, intrusion and torque) during orthodontic treatment with fixed appliance and clear aligners. METHODS: Thirty-two patients were included in this retrospective clinical study. Cone beam computed tomography (CBCT) was collected before and after treatment to measure the volume of dehiscence and fenestrations in the maxillary anterior region, anterior alveolar bone thickness and height and degree of tooth movement. Rank-sum tests were used to compare the differences in alveolar bone defect volumes between clear aligners and fixed appliance, multiple linear regression analysis was used for study evaluation, and kappa statistics were used to assess internal consistency and test-retest reliability. RESULTS: Post-operatively, most alveolar bone defects occurred on the labial side. The incidence of bone fenestration was 23.96% in the clear aligner group and 26.18% in the fixed appliance group, which was higher than the incidence of bone dehiscence (5.21%). The labial bone height decreased by 0.272 mm, and the palatal bone height increased by 0.617 mm for every 1 mm downward intrusion of the anterior tooth apex in the fixed appliance group. In the clear aligner group, there was no significant change in the labial bone height, and the palatal bone height decreased by 0.447 mm for every 1 mm of anterior tooth retraction coronally. CONCLUSIONS: In the fixed appliance group, anterior tooth intrusion and retraction may have led to alveolar bone resorption by its compression at the cervical level. This study provides a three-dimensional tooth movement evaluation method by using CBCT.

Salivary microbiomes vary among orthodontic appliances and associate with clinical periodontal parameters.

OBJECTIVE: To investigate the salivary bacterial communities during the first 6-month orthodontic treatment with Clear Aligners (CA) and Fixed Appliances (FA), and its correlation with clinical periodontal parameters. MATERIALS AND METHODS: Saliva and periodontal parameters were sampled from individuals wearing CA or FA before treatment (T0), and after 3- (T3) and 6-month (T6) treatments. Salivary bacterial communities characterized based on the 16S rRNA V3-V4 region were compared between FA and CA and correlated with clinical periodontal parameters. RESULTS: Probing Depth (PD) significantly increased at T6 in the FA group versus T0, whereas it remained stable in the CA group. The Shannon and Pielou indices were significantly higher in the FA group and significantly positively correlated with periodontal inflammation parameters. ß-diversity analysis revealed distinct communities between the FA group and CA group at T6. The relative abundances of 3 genera and 15 species were significantly higher in the FA group. Among the above appliance-type related taxa, bacterial genera Selenomonas, Stomatobaculum, Olsenella and Faecalicoccus and bacterial species Selenomonas_sputigena, Dialister_invisus, Olsenella_profus, Prevotella_buccae, Cryptobacterium_curtum and Clostridium_spiroforme were significantly positively associated with periodontal parameters. CONCLUSIONS: Orthodontic treatments trigger appliance-related salivary bacterial communities, highlighting the importance of developing appliance-orientated periodontal strategies during orthodontic treatments. Salivary bacterial communities harboured by patients wearing FA possess higher bacterial parameters which were associated with increasing PD, PI and Gingival Index.

Three-dimensional microanalysis of tooth movement during the first 6 months of orthodontic double retention.

INTRODUCTION: This study performed a 3-dimensional analysis of tooth movement during orthodontic retention to assess the effectiveness of double retention (fixed and removable) in preventing undesired tooth movement. METHODS: One hundred randomly selected patients were included at the initiation of double orthodontic retention with fixed retainers and vacuum-formed splints (recommended to be worn 22 h/d) in both arches. Intraoral scans were performed directly (T0), 1 month (n = 88), 3 months (T2) (n = 78), and 6 months (T3) (n = 66) after retainer bonding. Nine reference points were marked on each tooth in every patient. Subsequent scans were superimposed, and point displacement was calculated. Statistical analysis was performed using the R statistical software (version 4.2.2; R Core Team, Vienna, Austria). RESULTS: Sample size calculation determined at least 55 patients were needed. The total dropout between T0 and T3 was 34 patients (did not show up for appointment). The median absolute displacement value of a single point between T0 and T3 was 0.015 mm. The most stable teeth were mandibular central incisors, whereas the least stable were mandibular molars. Most tooth displacements occurred between T0 and T2, then slowed down significantly. CONCLUSIONS: Double orthodontic retention prevents major tooth displacements in most patients during the first 6 months of retention; however, larger, unpredictable single-tooth displacement may occur in individual patients.

Patients' perception of orthodontic retainers: a systematic review.

BACKGROUND: Orthodontic retainers are widely used to prevent relapses after orthodontic treatment; however, evidence about patients' perceptions of retainers is lacking. OBJECTIVE: To assess patients' perception of orthodontic retainers. SEARCH METHODS: PubMed, Web of Science, Scopus, LILACS, LIVIVO, Cochrane Library, and gray literature (Google Scholar) were searched without date or language restrictions. A manual search of the reference lists of the included articles was also performed. SELECTION CRITERIA: Studies comparing patients' perceptions of wearing orthodontic retainers were included. DATA COLLECTION AND ANALYSIS: According to the study design, the risk of bias (RoB) assessment was performed using RoB 2.0 or ROBINS-I. The level of evidence was assessed through the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) tool. RESULTS: Seventeen studies met the eligibility criteria. After the RoB assessment, 12 randomized controlled trials presented a high RoB, and 4 non-randomized controlled trials presented a moderate RoB. The certainty of evidence was classified as very low for the four assessed outcomes. The studies generally reported an initial temporary negative impact of orthodontic retainers. Different esthetic, functional, and ease-of-use advantages are reported using removable and fixed retainers. A quantitative analysis was not performed due to the considerable clinical and methodological heterogeneity among the studies. CONCLUSION: The current evidence, although very limited, suggests that orthodontic retainers have an initial negative impact related to discomfort and functional limitations, but they seem to regress over time. There is a preference for thermoplastic over Hawley-type retainers. However, thermoplastic retainers cause different functional difficulties, and bonded retainers present the advantage of affecting speech function less than orthodontic removable retainers, although they can facilitate oral hygiene problems. REGISTRATION: PROSPERO (CRD42022306665).

Treatment outcome comparison of Invisalign vs fixed appliance treatment in first premolar extraction patients.

INTRODUCTION: In this study, we compared the dentitional changes after Invisalign and conventional orthodontic treatment with 4 first premolar extractions. METHODS: This retrospective study included 57 patients whose orthodontic treatment involved the extraction of 4 first premolars because of bialveolar protrusion. A total of 27 patients were treated with Invisalign (mean age, 25.5 ± 5.2 years) and 30 patients with the fixed appliance (mean age, 24.4 ± 5.8 years). The angular and linear changes of the maxillary and mandibular central incisors, second premolars, first molars, and second molars were measured from the recordings on the basis of the lateral cephalograms taken before and after treatment. The angular changes of the canines and second premolars were measured using panoramic radiographs. RESULTS: The overbite and interincisal angle increased significantly in the Invisalign group compared with in the conventional fixed appliance group (P <0.05). The maxillary central incisors showed increased lingual tipping in the Invisalign group (P <0.05), whereas there was no statistically significant difference in the angular change of the mandibular incisors between groups (P >0.05). The maxillary first and second molars showed mesial tipping in the Invisalign group (P <0.05). The maxillary second premolars, first and second molars, and the mandibular second molars showed mesial movement in the Invisalign group (P <0.05). CONCLUSIONS: The Invisalign group showed more statistically significant lingual tipping of the maxillary central incisors, distal tipping of the maxillary canines, and mesial tipping of the maxillary first and second molars after maximum retraction of the anterior teeth compared with the fixed appliance group.